Function (Brief):

The DLS is comprised of muscles with a propensity to act synergistically; rarely do these muscles act as prime movers. This subsystem plays an important role in motion of the tibiofibular joints, hip joints, sacroiliac joints and spine, and may aid in proprioception by altering recruitment strategies based on the load and stretch imparted on the system during heel strike. The DLS is active during gait, forward bending (more so when knees are near full extension), and lumbar extension, and eccentrically decelerates spine flexion, hip flexion, and ankle inversion. Over-activity of the DLS may contribute to the following signs on the Overhead Squat Assessment: shoulders elevate, excessive lordosis (anterior pelvic tilt), knees bow in (functional valgus),